Claims:We Claim:

1. Acrylate/ Styrene acrylate polymers comprising graft copolymers of acrylate/styrene acrylate and ricinoleic acid-PU (polyurethane)-HEMA (Hydroxy ethyl methacrylate) adduct having HEMA terminal of ricinoleic acid-PU-HEMA adduct grafted on said acrylate/styrene acrylate polymers.
2. The Acrylate/ Styrene acrylate polymers as claimed in claim 1 as a stable emulsion including small polymer particle size in the range of 80-350 preferably about 140 nm and is long carbon chain based ricinoleic acid- PU-HEMA grafted styrene acrylate polymer particles in said emulsion providing for improved hydrophobicity and room temperature drying emulsion with enhanced anti-efflorescence attributes.

3. The Acrylate/ Styrene acrylate polymers as claimed in anyone of claims 1 or 2 wherein said graft copolymer of styrene acrylate and ricinoleic acid PU-HEMA adduct having ricinoleic acid- PU-HEMA adduct grafted on styrene acrylate polymer comprises 0.5-6 wt.% preferably 2 wt.% ricinoleic acid-PU-HEMA adduct grafted styrene acrylate polymer said styrene acrylate polymer having styrene in the levels of 10-30 wt.% preferably 20 wt.%, butyl acrylate (BA) in the levels of 10-30 wt.% preferably 20 wt.%, Hydroxy ethyl methacrylate (HEMA) in the levels of 0.5-6 wt.% preferably 2 wt%, Methacrylic acid (MAA) in the levels of 0.5-2.5 wt.% preferably 0.8 wt.%, Vinyl trimethoxy silane (VTMO) in the levels of 0.05-1 wt.% preferably 0.3 wt.%, Vinyl ester of Versatic acid 10 (Veova-10) in the levels of 0.1-5 wt.% preferably 1 wt.% in said emulsion.

4. The Acrylate/ Styrene acrylate polymers as claimed in anyone of claims 1-3 wherein said graft copolymer of acrylates and ricinoleic acid PU-HEMA adduct having ricinoleic acid- PU-HEMA adduct grafted on acrylate polymer comprises 0.5-6 wt.% preferably 2 wt.% ricinoleic acid-PU-HEMA adduct grafted acrylate polymer, said acrylate polymer having Methyl Methacrylate (MMA), in the levels of 10-30 wt.% preferably 21 wt.%, butyl acrylate (BA) in the levels of 10-30 wt.% preferably 20 wt.%, Hydroxy ethyl methacrylate (HEMA) in the levels of 0.5-6 wt.% preferably 2 wt%, Methacrylic acid (MAA) in the levels of 0.5-2.5 wt.% preferably 0.8 wt.%, Vinyl trimethoxy silane (VTMO) in the levels of 0.05-1 wt.% preferably 0.3 wt.%, Vinyl ester of Versatic acid 10 (Veova-10) in the levels of 0.1-5 wt.% preferably 1 wt.% in said emulsion.
5. The Acrylate/ Styrene acrylate polymers as anyone of claimed in claims 1-5 wherein said ricinoleic acid-PU-HEMA adduct comprises reaction product of 50-85 wt.% preferably 60-65 wt.% ricinoleic acid-PU adduct having 3.5-8 % preferably 7 % NCO, 20-25 wt.% n-butyl acrylate and 5-20 wt.% preferably 10-15 wt.% hydroxyethyl methacrylate.

6. The Acrylate/ Styrene acrylate polymers as claimed in anyone of claims 1-5 as a stable emulsion that is mechanically stable by maintaining viscosity levels of 50-150 gms preferably 50-70 gms at temperatures at 30?C passing accelerated storage stability at 50 ?C with required maintenance of particle size of the emulsion.

7. A process for preparing Acrylate/ Styrene acrylate polymers as claimed in anyone of claims 1-6 comprising two-stage process of
(i) Providing ricinoleic acid PU-HEMA adduct;
(ii) Providing monomers of acrylate/styrene acrylate polymers; and
emulsion polymerizing (ii) in presence of (i) such as to obtain Ricinoleic acid-PU-HEMA adduct grafted acrylate/ styrene acrylate polymer preferably as polymer particles in a stable emulsion.

8. The process for preparing Acrylate/ Styrene acrylate polymers as claimed in claim 7 wherein said stage (i) comprises the sub-steps of
(a) providing 40.03 g ricinoleic acid and reacting with 24.58 g isocyanate preferably Isophorone diisocyanate that was added slowly dropwise through dropping funnel for 3 hours in the presence of nitrogen atmosphere and at maximum temperatures of 70° C followed by maintaining the temperature at 70° C for 1 hour and reaching NCO levels of 7-% NCO,
(b) adding 21.00 g n-butyl acrylate to the above mixture of step (a) followed by cooling the reaction temperature to 50 ?C and adding 14.39 g hydroxyethyl methacrylate slowly dropwise through dropping funnel for 30 min and thereafter allowing 1 hour reaction time for completion of reaction and thereafter cooled to 45° C to obtain ricinoleic acid PU-HEMA adduct.

9. The process for preparing Acrylate/ Styrene acrylate polymers as claimed in anyone of claims 7 or 8 wherein
said stage (ii) comprises the sub-steps of
(1) preparing an initiator solution of potassium persulfate (PPS), and water,
(2) preparing pre emulsion (PE) of monomer, surfactant, and water; and

seeded emulsion polymerizing (1) and (2) by feeding pre-emulsion (PE) and by involving ricinoleic acid-PU-HEMA adduct of stage (i) in a water batch to attain said Ricinoleic acid-PU-HEMA adduct grafted acrylate/styrene acrylate polymer as a stable emulsion.

10. The process for preparing Acrylate/ Styrene acrylate polymers as claimed in claim 9 wherein said second stage of the two stage process involves
(I) Adding to a reactor demineralized water, Sodium lauryl ether sulfate (SLES), Atpol A5731/70N and sodium bicarbonate (SBC) as contents and heated to 80° C;

(II) Separately preparing two solutions:

(1) an initiator solution of potassium persulfate (PPS), and water, and

(2) a pre-emulsion (PE) of monomers including styrene in the levels of 10-30 wt.% preferably 20 wt.%, butyl acrylate (BA) in the levels of 10-30 wt.% preferably 20 wt.%, Hydroxy ethyl methacrylate (HEMA) in the levels of 0.5-6 wt.% preferably 2 wt.%, Methacrylic acid (MAA) in the levels of 0.5-2.5 wt.% preferably 0.8 wt.%, Vinyl trimethoxy silane (VTMO) in the levels of 0.05-1 wt.% preferably 0.3 wt.%, Vinyl ester of Versatic acid 10 (Veova-10) in the levels of 0.1-5 wt.% preferably 1 wt.%, 0.5-6 wt.% preferably 2 wt.% ricinoleic acid-PU-HEMA adduct ricinoleic acid-PU-HEMA adduct and water; OR

(2) a pre-emulsion (PE) of monomers including Methyl Methacrylate (MMA), in the levels of 10-30 wt.% preferably 21 wt.%, butyl acrylate (BA) in the levels of 10-30 wt.% preferably 20 wt.%, Hydroxy ethyl methacrylate (HEMA) in the levels of 0.5-6 wt.% preferably 2 wt.%, Methacrylic acid (MAA) in the levels of 0.5-2.5 wt.% preferably 0.8 wt.%, Vinyl trimethoxy silane (VTMO) in the levels of 0.05-1 wt.% preferably 0.3 wt.%, Vinyl ester of Versatic acid 10 (Veova-10) in the levels of 0.1-5 wt.% preferably 1 wt.%, 0.5-6 wt.% preferably 2 wt.% ricinoleic acid-PU-HEMA adduct ricinoleic acid-PU-HEMA adduct and water;

(III) Adding 5% of the above pre-emulsion (PE) (2) to said reactor contents at 80?C, followed by addition of above initiator solution (1) and the mixture was allowed for 15 minutes to produce latex seed particles, and 15 minutes thereafter remaining PE (2) was fed into the reaction kettle over a period of 240 minutes wherein after 45 minutes of PE feeding, VTMO monomer was added to the PE, and wherein after completion of PE feeding, a solution of TBHP and SFS were added separately to said reactor and thereafter the reaction was held for 45 minutes that was followed by cooling neutralizing and filtering through mesh to give desired sized polymer particles as a stable emulsion.

Dated this the 23rd day of March, 2022 Anjan Sen
Of Anjan Sen and Associates
(Applicants Agent)
IN/PA-199

, Description:FIELD OF INVENTION

The present invention provides for grafted acrylate/styrene acrylate polymer preferably as polymer particles stabilized in an emulsion preferably grafted with ricinoleic acid- PU-HEMA adduct providing for enhanced anti-efflorescence attributes. A seeded emulsion polymerization process to enable grafted acrylate/styrene acrylate polymer preferably as polymer particles stabilized in the emulsion is also provided.

BACKGROUND ART

It is common to see large and unsightly blotches or patches of a white crystalline formation on the face of paint walls. These patches are formed when water moving through a wall or water being driven out because of heat of hydration as cement stone is being formed, brings salts to the surface that are not commonly bound as part of the cement stone. As the water evaporates, it leaves the salt behind, which forms a white, fluffy deposit. The resulting white deposits are referred to as efflorescence.

There are several references available on anti-efflorescence emulsion, and reference is drawn to US4999218A that teaches efflorescence phenomena on mineral substrates that are prevented by coating the surface of the mineral substrates with aqueous polyacrylate dispersions and drying the coating, if necessary at elevated temperatures, by a process in which a mixture of (A) a dispersion of a copolymer of (a) (meth)acrylates of alkanols which are of 3 to 20 carbon atoms and have a tertiary CH group, (b) styrene, a-methylstyrene, methyl methacrylate, tert-butyl (meth)acrylate and/or (meth)acrylonitrile and (c) mono- and/or dicarboxylic acids of 3 to 5 carbon atoms and/or or their amides which may be substituted at the N atom by alkyl, and (B) an aromatic ketone is used for the coating, and the coating is exposed to ultraviolet light. This prior art while teaches anti-efflorescence by copolymer of styrene and acrylates though on mineral substrates involves temperature elevation or exposure to UV light for drying and hence does not teach room temperature drying emulsion. This prior patent particularly teaches efflorescence phenomena on mineral substrates that are prevented by coating the surface of the mineral substrates with aqueous polyacrylate dispersions and drying the coating, and does not disclose any product emulsion employed in the exterior primer to prevent efflorescence.

CN105440853A teaches long-acting anti-efflorescence primer which is prepared from the following components: water, cellulose, a pH regulator, a wetting agent, a dispersion agent, a filler, a pure acrylic emulsion, a film-forming auxiliary agent, an antifreezing agent, a bactericide, a mildew preventive, a defoaming agent, and a thickening agent. The long-acting anti-efflorescence primer overcomes the defects that a conventional external wall primer has poor efflorescence resistance and salting-out resistance and is unable to take the initiative to prevent efflorescence, and has the advantages of taking the initiative to prevent paint film efflorescence and being excellent in efflorescence resistance. Long-acting anti-accumulation of salt in the surface soil priming paint is taught that is characterized in that: that describes Microcrystalline cellulose is Natvosol, described pH adjusting agent is 2-amino-2-methyl-1-propanol, and thickening material is polyurethane thickener.
CN 111234616 discloses slurry that comprises (1) liquid material: 15-25 parts of styrene-acrylate copolymer emulsion (BLJ 6319), 15-25 parts of butadiene-styrene copolymer emulsion (Lipaton SB 29Y57), 40-50 parts of water, 0.1-1 part of preservative (isothiazolinones and/or 2, 2-dibromopropionamide), 0.5-1.5 parts of antifreeze (ethylene glycol, propylene glycol, etc.), 0.3-0.8 parts of thickener (cellulose ethers, polyacrylates, etc.) and 0.1-1 parts of defoamer (mineral oil and/or silicone-based); (2) powder material: 50-60 parts of sulfoaluminate cement, 20-40 parts of inorganic filler (quartz sand, talc, etc.), 0.1- 0.5 parts of water reducing agent (lignosulfonates, polycyclic aromatic salts, etc.), 0.1-0.5 part of anti-efflorescence agent (organosilicon hydrophobic powder, coal fly ash, etc.), 0.05-0.15 parts of water-retaining agent and 2-5 parts of metakaolin; wherein, the wt. ratio of liquid to powder material is (8-10):25. The anti-efflorescence agent used is an organosilicon hydrophobic powder, coal fly ash etc.
Synthesis and characterization of ricinoleic acid derived monomer and its application in aqueous emulsion and paints thereof, by Nikita Mhadeshwar, Kunal Wazarkar, Anagha S. Sabnis, Department of Polymer and Surface Engineering, Institute of Chemical Technology, Mumbai, India, Pigment & Resin Technology, Volume 48, Number 1, 2018, pp. 65-72(8), teaches preparation of acrylic functional ricinoleic acid monomer and incorporate it in conventional miniemulsion polymerization. Subsequently, paints were formulated to study the variation in final coating properties. Synthesis process involved the esterification of ricinoleic acid with 2-hydroxy methyl methacrylate in the presence of FASCAT-4100 catalyst. The final product of the reaction, methacrylated ricinoleic acid (MRA), was confirmed using Fourier-transform infrared spectroscopy and 1H-nuclear magnetic resonance spectroscopy and determining acid and iodine value. Further, MRA was incorporated in various concentrations (1, 2 and 3 Wt.%) along with methyl acrylate and butyl acrylate in conventional miniemulsion polymerization and paints were formulated thereof. It was observed that with the addition of MRA monomer, flexibility of emulsion films increased as indicated by glass transition temperature and elongation value (percentage). Moreover, with the addition of MRA monomer, improvement in mechanical and chemical properties of the coatings was observed. Even a low concentration MRA monomer (as low as 3 per cent) caused a significant reduction in the glass transition temperature of emulsion films. Thus, it can be efficiently used in applications such as adhesives and elastomeric coatings. The acrylic functional monomer derived from ricinoleic acid is unique and not yet incorporated in miniemulsion polymerization. The synthesized monomer can be used in coatings where low Tg emulsions are required. To further improve the properties copolymerization further with styrene is done and in this prior art esterification of ricinoleic acid takes place.
Synthesis of Biobased Polyurethane from Oleic and Ricinoleic Acids as the Renewable Resources via the AB-Type Self-Condensation Approach, Dnyaneshwar V. Palaskar†‡, Aurélie Boyer†‡, Eric Cloutet†‡, Carine Alfos§, and Henri Cramail*†‡Biomacromolecules 2010, 11, 5, 1202–1211 discloses Polyurethane (PU) from methyl oleate (derived from sunflower oil) and ricinoleic acid (derived from castor oil) was synthesized using the AB-type selfpolycondensation approach for the first time. In the present work, three novel AB-type monomers, namely, a mixture of 10-hydroxy-9-methoxyoctadecanoyl azide/9hydroxy-10-methoxyoctadecanoyl azide (HMODAz), 12-hydroxy-9-cis-octadecenoyl azide (HODEAz) and methyl-N-11-hydroxy-9-cis-heptadecen carbamate (MHHDC) were synthesized from methyl oleate and ricinoleic acid using simple reaction steps. Out of these, HMODAz and HODEAz monomers were polymerized by the acyl-azido and hydroxyl AB-type self-condensation approach, while MHHDC monomer was polymerized through AB-type self-condensation via transurethane reaction. The acylazido and hydroxyl self-condensations were carried out at various temperatures (50, 60, 80. and 110 °C) in bulk with and without catalyst. A FTIR study of the polymerization, using HMODAz at 80 °C without catalyst, indicates in situ formation of an intermediate isocyanate group in the first 15-30 min, and further onward, the molar mass increases as observed by SEC analysis. In the case of the MHHDC monomer, a transurethane reaction was used to obtain a similar PU (which was obtained by AB-type acyl-azido and hydroxyl self-condensation of HODEAz) in the presence of titanium tetrabutoxide as a catalyst at 130 °C. HMODAz, HODEAz, MHHDC, and corresponding polyurethanes were characterized by FTIR, 1H NMR, 13C NMR, and MALDI-TOF mass spectroscopy. Differential scanning calorimetric analysis of polyurethanes derived from HMODAz, HODEAz, and MHHDC showed two different glass transition temperatures for soft segments (at lower temperature) and hard segments (at higher temperature), indicating phase-separated morphology. Vide this prior art ricinoleic acid-PU system appears to be known.
An Insight on Castor Oil Based Polyurethane and Nanocomposites: Recent Trends and Development, January 2017, Polymer-Plastics Technology and Engineering 56(14) is directed to castor oil has gained momentous attention as a valuable bio-based monomer and a potential alternative to the current petrobased polyol for synthesizing polyurethane due to the presence of inherent hydroxyl group. In spite of its huge potentiality very little has been reviewed regarding the development of polyurethane from castor oil. This review thus highlights the recent trends and development in the field of polyurethane and its nanocomposite based on castor oil including its biodegradability and weatherability studies. Further, this review also provides an insight regarding the utilization of castor oil based polyurethane and its nanocomposite for coating application. Teaches thereunder in pg 15 (attached hereto) that in the first stage PU are prepared by the reaction of castor oil with different isocyanates, such as hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI) and isophorone diisocyanate (IPDI). In the subsequent stage the synthesized castor oil based PU gets polymerized with different acrylic and vinyl monomers such as alkyl acrylate, styrene, methacrylate, acrylic acid, acrylonitrile, ethylene glycol dimethylacrylate (EGDMA) and 2hydroxyethyl methacrylate (2-HEMA) to synthesize PU/IPN network structures. Thus teaches an IPN network and not any simple co-polymer/ Graft copolymer of styrene acrylate- (recinoleic acid PU-HEMA) through free radical polymerization.
US 2008/0214770 A1 teaches amphiphilic polymer compounds which have been prepared by a) reacting a di-, tri- or tetraglycidyl compound (A) with an optionally unsaturated reactive component (B) consisting of C8-C28-fatty acid, a C8-C28-alcohol or a second aryl C8-C28-amine, and then b) allowing the reaction product from stage a) to react with an aliphatic or aromatic polyisocyanate compound (C) and finally c) reacting the reaction product from stage b) with a poly alkylene oxide compound (D) of the general formula (I) in which R" is H or a linear or branched and optionally unsaturated aliphatic hydrocarbon radical having 1 to 12C atoms, R2 is a linear or branched and optionally unsaturated aliphatic hydrocarbon radical having 1 to 30 C atoms or phenyl, m is from 0 to 250, n is from 3 to 350 and X is from 1 to 12, and the ethylene oxide or higher alkylene oxide units can be arbitrarily distributed in the polyalkylene oxide compound (D). The polymer compounds proposed in accordance with this prior invention are suitable as agents for preventing or suppressing efflorescence on surfaces of cured, hydro metrically settable building materials and/or for hydrophobization of the corresponding hydraulically settable systems. Moreover, owing to the admixtures proposed in accordance with the invention, the corresponding products absorb substantially less water, with the result that frost damage and rapid rusting of the steel reinforcement can be substantially reduced. Hence eventually discloses castor oil-PU adduct.
US 2017/ 0327709 A1 is directed to water - based compositions that are resistant to dirt pickup, efflorescence, tannin bleed - through and surfactant leaching are described. The water-based composition includes a latex or water - dispersible polymer and a non - VOC UV - VIS (preferably, ultraviolet) absorber as a dirt pickup resistance additive. Methods of making water - based compositions including a non - VOC UV - VIS absorber as an additive are also described. Para [0058] In certain embodiments teaches the water - based latex or water - dispersible polymer described herein is derived from the polymerization of one or more emulsions containing ethylenically unsaturated monomers. Suitable ethylenically unsaturated monomers include, for example, acrylic acid, alkyl and alkoxy acrylates or methacrylates (e.g., methyl methacrylate, butyl acrylate, 2-ethyl hexyl acrylate, butyl methacrylate, and the like), vinyl esters of saturated carboxylic acids, monoolefins, conjugated dienes, optionally with one or more monomers, such as, for example, styrene, vinyl acetate, acrylonitrile, acrylamide, diacetone acrylamide, and vinyl chloride, and the like, Para [0075] teaches the involvement of ricinoleic acid as VOC coalescent. Ricinoleic acid is involved as a VOC coalescent and not involved as a ricinoleic acid-PU-HEMA adduct for exploring and promoting adhesion and hence anti-efflorescence.
Considering the prevailing state of the art, there is a need in the art to provide for grafted copolymers of styrene-acrylate that would eliminate efflorescence on the paint surface in not being a primer but being a stable emulsion used in exterior primer enabling improved anti-efflorescence.
OBJECTS OF THE INVENTION
It is thus the primary object of the present invention to provide for grafted copolymers of styrene-acrylate that would eliminate efflorescence on the paint surface in not being a primer but being an emulsion used in exterior primer capable of improved anti-efflorescence.
It is another object of the present invention to provide for grafted styrene acrylate polymer preferably as polymer particles preferably grafted with ricinoleic acid- PU-HEMA adduct which adduct in being hydrophobic would provide for enhanced anti-efflorescence attributes.
Yet another object of the present invention is to provide for ricinoleic acid-PU-HEMA adduct grafted styrene acrylate copolymers which would be stabilized in an emulsion of smaller particle size to provide for greater hydrophobicity and hence enhanced anti-efflorescence attributes.
Still another object of the present invention is to provide for an emulsion polymerization process which based on its process parameters, time and temperature of addition of the seed would provide for a stable emulsion containing said copolymer as copolymer particles with smaller particle size to garner desired hydrophobicity and in turn enhanced anti-efflorescence attributes.

SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention there is provided acrylate/ styrene acrylate polymers comprising graft copolymers of acrylate/styrene acrylate and ricinoleic acid-PU (polyurethane)-HEMA (Hydroxy ethyl methacrylate) adduct having HEMA terminal of ricinoleic acid-PU-HEMA adduct grafted on said acrylate/styrene acrylate polymers.
Preferably the acrylate/ Styrene acrylate polymers are provided as a stable emulsion including small polymer particle size in the range of 80-350 preferably about 140 nm and is long carbon chain based ricinoleic acid- PU-HEMA grafted styrene acrylate polymer particles in said emulsion providing for improved hydrophobicity and room temperature drying emulsion with enhanced anti-efflorescence attributes.
According to an aspect of the present invention there is provided said acrylate/ Styrene acrylate polymers wherein said graft copolymer of styrene acrylate and ricinoleic acid PU-HEMA adduct having ricinoleic acid- PU-HEMA adduct grafted on styrene acrylate polymer comprises 0.5-6 wt.% preferably 2 wt.% ricinoleic acid-PU-HEMA adduct grafted styrene acrylate polymer said styrene acrylate polymer having styrene in the levels of 10-30 wt.% preferably 20 wt.%, butyl acrylate (BA) in the levels of 10-30 wt.% preferably 20 wt.%, Hydroxy ethyl methacrylate (HEMA) in the levels of 0.5-6 wt.% preferably 2 wt%, Methacrylic acid (MAA) in the levels of 0.5-2.5 wt.% preferably 0.8 wt.%, Vinyl trimethoxy silane (VTMO) in the levels of 0.05-1 wt.% preferably 0.3 wt.%, Vinyl ester of Versatic acid 10 (Veova-10) in the levels of 0.1-5 wt.% preferably 1 wt.% in said emulsion.
Preferably said acrylate/ styrene acrylate polymers are graft copolymer of acrylates and ricinoleic acid PU-HEMA adduct having ricinoleic acid- PU-HEMA adduct grafted on acrylate polymer comprises 0.5-6 wt.% preferably 2 wt.% ricinoleic acid-PU-HEMA adduct grafted acrylate polymer, said acrylate polymer having Methyl Methacrylate (MMA), in the levels of 10-30 wt.% preferably 21 wt.%, butyl acrylate (BA) in the levels of 10-30 wt.% preferably 20 wt.%, Hydroxy ethyl methacrylate (HEMA) in the levels of 0.5-6 wt.% preferably 2 wt%, Methacrylic acid (MAA) in the levels of 0.5-2.5 wt.% preferably 0.8 wt.%, Vinyl trimethoxy silane (VTMO) in the levels of 0.05-1 wt.% preferably 0.3 wt.%, Vinyl ester of Versatic acid 10 (Veova-10) in the levels of 0.1-5 wt.% preferably 1 wt.% in said emulsion.
According to another aspect of the present invention there is provided said acrylate/ styrene acrylate polymers wherein said ricinoleic acid-PU-HEMA adduct comprises reaction product of 50-85 wt.% preferably 60-65 wt.% ricinoleic acid-PU adduct having 3.5-8 % preferably 7 % NCO, 20-25 wt.% n-butyl acrylate and 5-20 wt.% preferably 10-15 wt.% hydroxyethyl methacrylate.

Preferably said acrylate/ styrene acrylate polymers are a stable emulsion that is mechanically stable by maintaining viscosity levels of 50-150 gms preferably 50-70 gms at temperatures at 30?C passing accelerated storage stability at 50 ?C with required maintenance of particle size of the emulsion.

According to another aspect of the present invention there is provided a process for preparing acrylate/ styrene acrylate polymers comprising two-stage process of
(i) Providing ricinoleic acid PU-HEMA adduct;
(ii) Providing monomers of acrylate/styrene acrylate polymers; and
emulsion polymerizing (ii) in presence of (i) such as to obtain Ricinoleic acid-PU-HEMA adduct grafted acrylate/ styrene acrylate polymer preferably as polymer particles in a stable emulsion.

Preferably in said process for preparing acrylate/ styrene acrylate polymers wherein said stage (i) comprises the sub-steps of
(a) providing 40.03 g ricinoleic acid and reacting with 24.58 g isocyanate preferably Isophorone diisocyanate that was added slowly dropwise through dropping funnel for 3 hours in the presence of nitrogen atmosphere and at maximum temperatures of 70° C followed by maintaining the temperature at 70° C for 1 hour and reaching NCO levels of 7-% NCO,
(b) adding 21.00 g n-butyl acrylate to the above mixture of step (a) followed by cooling the reaction temperature to 50 ?C and adding 14.39 g hydroxyethyl methacrylate slowly dropwise through dropping funnel for 30 min and thereafter allowing 1 hour reaction time for completion of reaction and thereafter cooled to 45° C to obtain ricinoleic acid PU-HEMA adduct.

Preferably in said process for preparing acrylate/ styrene acrylate polymers wherein
said stage (ii) comprises the sub-steps of
(1) preparing an initiator solution of potassium persulfate (PPS), and water,
(2) preparing pre emulsion (PE) of monomer, surfactant, and water; and

seeded emulsion polymerizing (1) and (2) by feeding pre-emulsion (PE) and by involving ricinoleic acid-PU-HEMA adduct of stage (i) in a water batch to attain said Ricinoleic acid-PU-HEMA adduct grafted acrylate/styrene acrylate polymer as a stable emulsion.

According to another preferred aspect of the process for preparing acrylate/ styrene acrylate polymers wherein said second stage of the two stage process involves
(I) Adding to a reactor demineralized water, Sodium lauryl ether sulfate (SLES), Atpol A5731/70N and sodium bicarbonate (SBC) as contents and heated to 80° C;

(II) Separately preparing two solutions:

(1) an initiator solution of potassium persulfate (PPS), and water, and

(2) a pre-emulsion (PE) of monomers including styrene in the levels of 10-30 wt.% preferably 20 wt.%, butyl acrylate (BA) in the levels of 10-30 wt.% preferably 20 wt.%, Hydroxy ethyl methacrylate (HEMA) in the levels of 0.5-6 wt.% preferably 2 wt.%, Methacrylic acid (MAA) in the levels of 0.5-2.5 wt.% preferably 0.8 wt.%, Vinyl trimethoxy silane (VTMO) in the levels of 0.05-1 wt.% preferably 0.3 wt.%, Vinyl ester of Versatic acid 10 (Veova-10) in the levels of 0.1-5 wt.% preferably 1 wt.%, 0.5-6 wt.% preferably 2 wt.% ricinoleic acid-PU-HEMA adduct ricinoleic acid-PU-HEMA adduct and water; OR

(2) a pre-emulsion (PE) of monomers including Methyl Methacrylate (MMA), in the levels of 10-30 wt.% preferably 21 wt.%, butyl acrylate (BA) in the levels of 10-30 wt.% preferably 20 wt.%, Hydroxy ethyl methacrylate (HEMA) in the levels of 0.5-6 wt.% preferably 2 wt.%, Methacrylic acid (MAA) in the levels of 0.5-2.5 wt.% preferably 0.8 wt.%, Vinyl trimethoxy silane (VTMO) in the levels of 0.05-1 wt.% preferably 0.3 wt.%, Vinyl ester of Versatic acid 10 (Veova-10) in the levels of 0.1-5 wt.% preferably 1 wt.%, 0.5-6 wt.% preferably 2 wt.% ricinoleic acid-PU-HEMA adduct ricinoleic acid-PU-HEMA adduct and water;

(III) Adding 5% of the above pre-emulsion (PE) (2) to said reactor contents at 80?C, followed by addition of above initiator solution (1) and the mixture was allowed for 15 minutes to produce latex seed particles, and 15 minutes thereafter remaining PE (2) was fed into the reaction kettle over a period of 240 minutes wherein after 45 minutes of PE feeding, VTMO monomer was added to the PE, and wherein after completion of PE feeding, a solution of TBHP and SFS were added separately to said reactor and thereafter the reaction was held for 45 minutes that was followed by cooling neutralizing and filtering through mesh to give desired sized polymer particles as a stable emulsion.

DETAILED DESCRIPTION OF THE INVENTION
As discussed hereinbefore, the present invention provides for grafted acrylate/ styrene acrylate polymer preferably as polymer particles stabilized as an emulsion preferably grafted with ricinoleic acid- PU-HEMA adduct which grafted adduct in being hydrophobic provides for enhanced anti-efflorescence attributes.
A method of synthesizing acrylate/styrene acrylate Ricinoleic acid-PU-HEMA adduct polymeric particles is also provided. A two-stage process has been employed. First, Ricinoleic acid–PU terminated with HEMA adduct was synthesized. This adduct along with styrene, acrylate monomers are polymerized by emulsion polymerization process preferably seeded emulsion polymerization process to enable Ricinoleic acid-PU-HEMA adduct grafted styrene acrylate polymer preferably as polymer particles. The resulting emulsion showed 5 times better anti efflorescence properties than existing standard emulsion in exterior primer.
In said method of synthesis, the graft copolymer is provided as a major product with the HEMA terminal of the PU macromonomer (adduct) end that grafts onto the styrene-acrylic/ pure acrylic backbone.
However, sometimes due to the presence of two HEMA moieties on both sides of the macromonomer (adduct), then the adduct also acts as a flexible crosslinker. During synthesis of the adduct from NCO-terminated PU intermediates, HEMA going on both sides of the adduct is also possible which is minimized in the reaction based on the select wt.% of the reagents involved in the method that maximizes the one-side HEMA terminated adduct by stoichiometric control of the PU intermediate to HEMA ratio/ wt.%. The double HEMA terminated adduct molecules are formed as a minor component, along with the single HEMA terminated major component, wherein the minor component remains as a part of the resultant adduct and cannot be separated. The anti-efflorescence property degrades when the minor component excels in the acrylate/ styrene acrylate polymers of the present invention which again co-operates with the wt.% monomers constituting the acrylate/ styrene acrylate polymers.

The emulsion of the present invention is different from other available anti efflorescence emulsion in the following respects:
1. Involvement of Ricinoleic acid-PU-HEMA adduct by seeded emulsion polymerization for grafting styrene acrylate polymer
2. Excellent anti efflorescence properties.
Comparative data on quantifications of anti-efflorescence properties achieved by following some known standards of measurements illustrating that specific Ricinoleic acid – PU terminated HEMA adduct only when prior synthesized by way of the present invention and then polymerized with styrene & acrylate monomers via seeded emulsion polymerization (in accordance with the invention) - could result in 5 fold enhancement in anti-efflorescence attributes vis-à-vis less or no enhancement of various other ricinoleic acid-PU-X/HEMA-styrene acrylate adducts.
EXAMPLES:-
The reactor charges below are exemplified with the most preferred amounts and the ranges covered continue to be within the scope with the reactions that remains non-workable to get the desired attributes once the wt.% ranges as mentioned above are not followed.
Synthesis of Ricinoleic acid based urethane adduct
40.03 grams Ricinoleic acid was taken in reactor fitted with reflux condenser, stirrer, thermo-couple and nitrogen inlet. In presence of nitrogen atmosphere, 24.58 grams Isophorone diisocyanate was added slowly dropwise through dropping funnel for 3 hours to the above with constant stirring. After addition completion, maximum temperature was raised to 70° C. Temperature was maintained at 70° C for 1 hour. Percentage isocyanate content (% NCO) was checked by dibutylamine back titration. Experimental % NCO was 7.06 % (Theoretical value: 7.19 %). If the % NCO is not reached the theoretical value then the reaction is to continue till to get theoretical % NCO. After reaching desired % NCO, 21.00 grams n-butyl acrylate was added to the above under stirring. After well mixing of adduct in n-butyl acrylate, the contents in reactor was cooled to 50° C. After reaching temperature 50° C, 14.39 grams hydroxyethyl methacrylate was added slowly dropwise through dropping funnel for 30 min to the above with constant stirring and allowed for 1 hour for reaction completion. The contents in the reactor was cooled to 45° C, discharged and filtered the batch.
Butyl acrylate acts as a diluents while hydroxyl group of HEMA reacts with NCO group at 50?C without any catalyst.

Emulsion synthesis involving Ricinoleic acid based urethane adduct

Example 1 & 2 & 3: A 1 liter glass kettle equipped with a mechanical stirrer, reflux condenser, thermometer and inlet tube for pre emulsion feeding is placed in a water batch. The demineralized water, Sodium lauryl ether sulfate (SLES), Atpol A5731/70N and sodium bicarbonate (SBC) were added to the glass kettle. The mixture was then gradually heated to 80° C under stirring at 200 rpm. Separately two solutions were prepared in the flask: (1) an initiator Solution of potassium persulfate (PPS), and water, (2) a pre emulsion (PE) of monomer, surfactant, and water.
5% of the above pre-emulsion was added to the kettle at 80?C, followed by addition of above initiator solution. The mixture was allowed for 15 minutes to produce latex seed particles. After 15 minutes, remaining PE was fed into the reaction kettle over a period of 240 minutes. After 45 minutes of PE feeding, VTMO monomer was added to the PE flask. After completing the feeding of PE, a solution of TBHP and SFS were added separately into the kettle. The reaction was held for 45 minutes. The reaction was cooled down to room temperature and ammonia solution and Kathon LX 150 were added to the reaction kettle. The resulting emulsion was filtered through 80 nylon-mesh.

Table 1:

Ingredients Example 1 Example 2 Example 3
Reactor Charge Wt% Wt% Wt%
SLES 0.3 0.3 0.3
Atpol A5731/70N
0.2 0.2 0.2
SBC 0.12 0.12 0.12
DMW 16 16 16

Initiator solution
PPS 0.1 0.1 0.1
DMW 2.5 2.5 2.5

Pre emulsion (PE)
DMW 26 26 26
SLES 0.4 0.4 0.4
Atpol 5731/70N 0.4 0.4 0.4
PPS 0.08 0.08 0.08
Styrene 21 23.5 -
MMA - - 21
BA 21 23.5 22
Veova-10 1 - -
HEMA 2 - 2
MAA 0.8 0.8 0.8
Ricinoleic acid based urethane adduct 2 - 2

Add After 45 mins in PE
VTMO 0.3 0.3 0.3
DMW 0.5 0.5 0.5

Solution
TBHP 0.05 0.05 0.05
DMW 1 1 1
SFS 0.05 0.05 0.05
DMW 1 1 1

Ammonia solution 0.6 0.6 0.6
Kathon LX150 0.2 0.2 0.2
DMW 2.4 2.4 2.4

Methyl Methacrylate (MMA), Hydroxy ethyl methacrylate (HEMA), Butyl acrylate (BA), Methacrylic acid (MAA), sodium bicarbonate (SBC), potassium persulfate (PPS), and water (DMW). Sodium lauryl ether sulfate (SLES). Vinyl trimithoxy silane (VTMO), Vinyl ester of Versatic acid 10 (Veova-10).

Properties of the emulsion:
Table 2:

S No Description Example 1 Example 2 Example 3
1 pH 9.3 9.3 9
2 % NVM 49 49 49
3 Viscosity [gms] 54 70 74
4 Particle size (nm) 150 130 150
5 Mechanical stability Stable Stable stable
6 Accelerated stability (@ 50?C,15 days) Initial viscosity & final viscosity Pass

Pass

Pass
7 Electrolytic stability ml/100 g 16 16 16

In the experiments it is seen that simple styrene acrylate/ acrylate emulsions do fail at providing anti-efflorescence resistance. As they lack in providing higher adhesion as total percentage of polymerizable acids present in the formulations is very less and are partially neutralized to ensure their freeze thaw and mechanical stability. Acids and hydroxyl groups are mostly responsible for adhesion. Long carbon chain of ricinoleic acid- PU-HEMA grafting in the desired wt% ranges provides greater hydrophobicity. These properties all together with Adhesion, Hydrophobicity and small particle size provides enhanced anti-efflorescence attributes.
Further the anti-efflorescence attributes of the present invention do not involve temperature elevation or exposure to UV light for drying nor involves any organosilicon hydrophobic powder, coal fly ash etc. It is a normal room temperature drying emulsion which emulsion can be used in exterior primer to prevent efflorescence.
Neither PU is involved as a thickening agent nor the polymer attained by way of the present invention is a pure acrylic system, nor, does it involve esterified ricinoleic acid, nor, does it involve any IPN (interpenetrating polymer network) network, but is a simple styrene acrylate/ acrylate system having thereon grafted Ricinoleic acid-PU-HEMA adduct and therefore is a co-polymer/ Graft copolymer of acrylate/ styrene acrylate - (ricinoleic acid PU-HEMA) obtained through free radical polymerization wherein the ricinoleic acid-PU-HEMA adduct at desired levels promotes adhesion and hence anti-efflorescence and emulsion stability. The product polymer is not directly a primer but is an emulsion used in exterior primer enabling improved anti-efflorescence properties as per below.
Standard of measurement followed for measuring anti-efflorescence properties:
Wick test for efflorescence of building brick, John W. McBurney and Douglas E. Parsons, Nation Bureau of Standards, volume 19, July 1937
Table 3:
Sr. no. Classification/ Rating /Grade Description
1 None (0) No observable difference in the appearance of a brick after test and before.
2 Trace (1) Efflorescence barely distinguishable by careful comparison.
3 Slight (2) Observable. Not sufficient efflorescence to materially affect the appearance when viewed at a distance of approximately 6 ft.
4 Moderate (3) Distinct coating, but the original color of the brick distinguishable under the efflorescence.
5 Considerable (4) The original color of the brick masked by the efflorescence.
6 Abundant (5) Efflorescence in such quantity that it may be brushed off readily.

Experimental and rating based on the above test methodology:
Sample Name Rating
Styrene Acrylate/ Acrylate 5
Ricinoleic acid-PU-HEMA adduct (graft copolymer of styrene acrylate/ acrylate - ricinoleic acid PU-HEMA adduct) 0, No observable difference in the appearance of a brick after test and before.

It is thus possible by way of the present advancement to provide for grafted acrylate/styrene acrylate polymer preferably as polymer particles stabilized in an emulsion preferably grafted with ricinoleic acid- PU-HEMA adduct providing for enhanced anti-efflorescence attributes attained based on seeded emulsion polymerization process to enable grafted styrene acrylate/a crylate polymer preferably as polymer particles stabilized in the emulsion.